牙鲆不同家系生长性能比较及优良亲本选择

针对牙鲆生长慢的问题，实验室建立了63个牙鲆家系生长性能进行了测定和比较分析。对日龄80～230 d的不同家系鱼苗的体长和体重进行了测量，发现家系之间存在明显的生长差异，生长最快家系平均体重是最慢家系的3.08倍，最大体长是最小体长的1.47倍。家系的绝对增重率分布在0.138～0.478。利用多元方差分析（MANOVA）对家系因子进行分析表明，牙鲆家系生长日龄对家系体长和体重未达显著影响（P>0.05）；利用单因素方差（one-way ANOVA）分析和多重比较法（SNK）对63个家系的生长指标进行分析比较后表明，所有家系可分为生长快速、生长较快、生长一般、生长较慢和生长最慢5个组，5组之间具有显著性差异（P<0.01），筛选出19、36、51、21、69、61、64和81号8个生长快速家系。利用多重比较法对RS♂×JS♀、RS♂×RS♀、RS♂×YS♀、JS♂×RS♀、JS♂×JS♀、YS♂×RS♀、YS♂×JS♀　7个杂交组合产生的后代生长性状进行综合分析，发现JS♂×RS♀杂交产生的家系生长最快（P<0.05），不同群体间与群体内杂交产生家系在生长上存在着明显的差异（P<0.05）。利用半同胞家系进行后裔性状测定和分析，对牙鲆3个群体中14个父本和12个母本的生长遗传性状进行鉴定，发现JS29、JS12 和RS41　3个父本及 RS75、RS28、RS86、JS21和JS22　5个母本产生的家系生长较快（P<0.05）。利用生长最快家系和生长最慢家系的体长和体重数据，建立了体长和体重关系式，决定系数R²>0.5、a值相近、b<3，表明家系个体的体长和体重密切相关，家系生长环境较稳定，两家系都处于异速生长阶段。

The comparison of growth performances of Japanese flounder (Paralichthys olivaceus) families and selection of parents with good trait

Japanese flounder (Paralichthys olivaceus) is one of the most important fishes for mariculture in China as it is fast growing and has high market value. However, in recent years, the Japanese flounder aquaculture encountered many problems such as disease, decreased growth rate and germplasm degradation etc. So, it is very important to breed new strains with high growth rate and disease resistance in flounder aquaculture. In the present study, the growth characteristics of 63 flounder families developed previously in our lab were compared. The body length and body weight of 80 -230 d individuals from these families were measured and the results showed that the significant growth differences among families have been found. The average body length and average body weight of individuals from family with the fastest growth rate were 1.47 and 3.08 times than those of family with the slowest growth rate, respectively, and the absolute growth rate among these families ranges from 0. 138 to 0. 478. The multivariate analysis of variance (MANOVA) to family factors showed that the growth days of flounder family did not have significant influence on the body length and weight (P >0.05). The one way AVOVE and SNK analysis for 63 family growth characterization revealed that all families could be divided into 5 groups including the fastest growth, fast growth, normal growth, slow growth and the slowest growth group with significant difference (P < 0.01). From these groups, eight fast growth families numbers of 19, 36, 51, 21, 69, 61, 64 and 81 were selected. The offspring growth characterization of seven cross combinations including RS ♂ × JS ♀ , RS ♂ × RS ♀ , RS ♂ × YS ♀ , JS ♂ × RS♀ , JS ♂ × JS ♀, YS ♂ × RS ♀ and YS ♂ × JS ♀ was analyzed with SNK method, and the results revealed that the JS ♂ × RS ♀ hybridization family grew faster (P < 0. 05) and the obvious significant difference in the growth speed of family from different stock cross and same stock cross (P<0.05). The progeny testing of half-sib family suggested the JS29, JS12, RS41 paternity and RS75, RS28, RS86, JS21, JS22 maternity possessed the excellent growth genes owing to their offspring fast growth speed (P <0.05). Finally, based on these body length and weight data of the fastest and slowest growth family, the body length and weight relationship was constructed with correlation coefficient R~2 >0.5, the similar a value and b <3. And this showed that the family individual body length and weight had close relation and two kinds of families in stable growth environment were in allometric growth period.